423 research outputs found
Stress Distribution on Edentulous Mandible and Maxilla Rehabilitated by Full-Arch Techniques: A Comparative 3D Finite-Element Approach
In this paper biomechanical interaction between osseointegrated dental implants and bone
is numerically investigated through 3D linearly elastic finite-element analyses, when static
functional loads occur. Influence of some mechanical and geometrical parameters on bone
stress distribution is highlighted and risk indicators relevant to critical overloading of bone
are introduced. Insertions both in mandibular and maxillary molar segments are analyzed,
taking into account different crestal bone loss configurations. Stress-based performances of
five commercially-available dental implants are evaluated, demonstrating as the optimal
choice of an endosseous implant is strongly affected by a number of shape parameters
as well as by anatomy and mechanical properties of the site of placement. Moreover, effectiveness
of some double-implant devices is addressed. The first one is relevant to a partially
edentulous arch restoration, whereas other applications regard single-tooth restorations
based on non-conventional endosteal mini-implants. Starting from computer tomography
images and real devices, numerical models have been generated through a parametric
algorithm based on a fully 3D approach. Furthermore, effectiveness and accuracy of
finite-element simulations have been validated by means of a detailed convergence
analysis
Novena alla S. Madre Teresa di Giesu ... divisa in nove mercoledi
Copia digital : Junta de Castilla y León. Consejería de Cultura y Turismo, 2014Sign.: A-D8, E4
Vita della serafica vergine S. Madre Teresa de Giesu : compendio descritta e novena alla medesima Santa
Copia digital. Valladolid : Junta de Castilla y León. Consejería de Cultura y Turismo, 2013Sign.: a4, A-Z8, 2A8.Front. calc
Breaking Symmetry Rules Enhance the Options for Stereoselective Propene Polymerization Catalysis
An example of breaking "Ewen's symmetry rule" for olefin catalysis polymerization is proposed by DFT calculations. Catalyst precursors with Cs symmetry are suggested to promote the isotactic propene polymerization by a modification of the active site geometry obtained via coordination with AlH-alkyl species in solution. The origin of stereocontrol in olefin polymerization is due to a dual mechanism dictated by the chiral catalyst. These findings may expand the toolbox for promoting stereoselective olefin polymerization by transition metal catalysts
Natural Little Hierarchy from a Partially Goldstone Twin Higgs
We construct a simple theory in which the fine-tuning of the standard model
is significantly reduced. Radiative corrections to the quadratic part of the
scalar potential are constrained to be symmetric under a global U(4) x U(4)'
symmetry due to a discrete Z_2 "twin" parity, while the quartic part does not
possess this symmetry. As a consequence, when the global symmetry is broken the
Higgs fields emerge as light pseudo-Goldstone bosons, but with sizable quartic
self-interactions. This structure allows the cutoff scale, \Lambda, to be
raised to the multi-TeV region without significant fine-tuning. In the minimal
version of the theory, the amount of fine-tuning is about 15% for \Lambda = 5
TeV, while it is about 30% in an extended model. This provides a solution to
the little hierarchy problem. In the minimal model, the "visible" particle
content is exactly that of the two Higgs doublet standard model, while the
extended model also contains extra vector-like fermions with masses ~(1-2)TeV.
At the LHC, our minimal model may appear exactly as the two Higgs doublet
standard model, and new physics responsible for cutting off the divergences of
the Higgs mass-squared parameter may not be discovered. Several possible
processes that may be used to discriminate our model from the simple two Higgs
doublet model are discussed for the LHC and for a linear collider.Comment: 22 page
Pisa Syndrome in Parkinson's Disease: evidence for bilateral vestibulospinal dysfunction
Introduction. Pisa syndrome (PS) is a postural complication of Parkinson's disease (PD). Yet, its pathophysiology remains unclear, although a multifactorial component is probable. Cervical vestibular evoked myogenic potentials (cVEMPs) explore vestibulospinal pathway, but they have not been measured yet in PD patients with PS (PDPS) to assess a potential vestibular impairment. Materials and Methods. We enrolled 15 PD patients, 15 PDPS patients, and 30 healthy controls (HCs). They underwent neurological examination and were examined with Unified Parkinson's Disease Rating Scale II-Ill (UPDRSII-III), audiovestibular workup, and cVEMP recordings. Data were analysed with Chi-square, one-way ANOVA, multinomial regression, nonparametric, and Spearman's tests. Results. cVEMPs were significantly impaired in both PD and PDPS compared with HCs. PDPS exhibited more severe cVEMP abnormalities with prevalent bilateral loss of potentials, compared with the PD group, in which a prevalent unilateral loss was instead observed. No clinical-neurophysiological correlations emerged. Conclusions. Differently from HC, cVEMPs are altered in PD. Severity of cVEMPs alterations increases from PD without PS to PDPS, suggesting an involvement of vestibulospinal pathway in the pathophysiology of PS. Our results provide evidence for a significant impairment of cVEMPs in PDPS patients and encourage further studies to test validity of cVEMPs as diagnostic and prognostic biomarkers of PD progression
Lipoprotein(a) as a Risk Factor for Cardiovascular Diseases: Pathophysiology and Treatment Perspectives
Cardiovascular disease (CVD) is still a leading cause of morbidity and mortality, despite all the progress achieved as regards to both prevention and treatment. Having high levels of lipoprotein(a) [Lp(a)] is a risk factor for cardiovascular disease that operates independently. It can increase the risk of developing cardiovascular disease even when LDL cholesterol (LDL-C) levels are within the recommended range, which is referred to as residual cardiovascular risk. Lp(a) is an LDL-like particle present in human plasma, in which a large plasminogen-like glycoprotein, apolipoprotein(a) [Apo(a)], is covalently bound to Apo B100 via one disulfide bridge. Apo(a) contains one plasminogen-like kringle V structure, a variable number of plasminogen-like kringle IV structures (types 1–10), and one inactive protease region. There is a large inter-individual variation of plasma concentrations of Lp(a), mainly ascribable to genetic variants in the Lp(a) gene: in the general po-pulation, Lp(a) levels can range from 1000 mg/dL. Concentrations also vary between different ethnicities. Lp(a) has been established as one of the risk factors that play an important role in the development of atherosclerotic plaque. Indeed, high concentrations of Lp(a) have been related to a greater risk of ischemic CVD, aortic valve stenosis, and heart failure. The threshold value has been set at 50 mg/dL, but the risk may increase already at levels above 30 mg/dL. Although there is a well-established and strong link between high Lp(a) levels and coronary as well as cerebrovascular disease, the evidence regarding incident peripheral arterial disease and carotid atherosclerosis is not as conclusive. Because lifestyle changes and standard lipid-lowering treatments, such as statins, niacin, and cholesteryl ester transfer protein inhibitors, are not highly effective in reducing Lp(a) levels, there is increased interest in developing new drugs that can address this issue. PCSK9 inhibitors seem to be capable of reducing Lp(a) levels by 25–30%. Mipomersen decreases Lp(a) levels by 25–40%, but its use is burdened with important side effects. At the current time, the most effective and tolerated treatment for patients with a high Lp(a) plasma level is apheresis, while antisense oligonucleotides, small interfering RNAs, and microRNAs, which reduce Lp(a) levels by targeting RNA molecules and regulating gene expression as well as protein production levels, are the most widely explored and promising perspectives. The aim of this review is to provide an update on the current state of the art with regard to Lp(a) pathophysiological mechanisms, focusing on the most effective strategies for lowering Lp(a), including new emerging alternative therapies. The purpose of this manuscript is to improve the management of hyperlipoproteinemia(a) in order to achieve better control of the residual cardiovascular risk, which remains unacceptably high
Sustained Effectiveness of Benralizumab in Naïve and Biologics-Experienced Severe Eosinophilic Asthma Patients: Results from the ANANKE Study
Purpose: Severe eosinophilic asthma (SEA) patients often present overlapping inflammatory features rendering them eligible for multiple biologic therapies; switching biologic treatment is a strategy adopted to optimize asthma control when patients show partial or no response to previous biologics. Patients and Methods: ANANKE is a retrospective, multicenter Italian study (NCT04272463). Here, we outline the characteristics and long -term clinical outcomes in naive-to-biologics and biologics-experienced patients treated with benralizumab for up to 96 weeks. Bioexperienced patients were split into omalizumab and mepolizumab subsets according to the type of biologic previously used. Results: A total of 124 (76.5%) naive and 38 (23.5%) bio-experienced patients were evaluated at index date; 13 patients (34.2%) switched from mepolizumab, 21 patients (55.3%) switched from omalizumab, and four patients (10.5%) received both biologics. The mepolizumab subset was characterized by the longest SEA duration (median of 4.6 years), the highest prevalence of chronic rhinosinusitis with nasal polyposis (CRSwNP) (76.5%), and the greatest oral corticosteroid (OCS) daily dosage (median of 25 mg prednisone equivalent). The omalizumab group showed the highest severe annual exacerbation rate (AER) (1.70). At 96 weeks, treatment with benralizumab reduced any and severe AER by more than 87% and 94%, respectively, across all groups. Lung function was overall preserved, with major improvements observed in the mepolizumab group, which also revealed a 100% drop of the median OCS dose. Asthma Control Test (ACT) score improved in the naive group while its increment was more variable in bio-experienced patients; among these, a marked difference was noticed between omalizumab and mepolizumab subsets (median ACT score of 23.5 and 18, respectively). Conclusion: Benralizumab promotes durable and profound clinical benefits in naive and bio-experienced groups, indicating that a nearly complete depletion of eosinophils is highly beneficial in the control of SEA, independently of previous biologic use
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